Apparatus and method for cooling electronic systems

ABSTRACT

A method and apparatus for cooling electronic systems includes a field and/or customer replaceable packaged refrigeration module coupled to tubing formed in, or on, the chassis of the electronic system. The field replaceable packaged refrigeration module portion is self-contained and is specifically designed to have physical dimensions similar to those of a standard air-based cooling system, such as a fined heat sink or heat pipe. The coupling of the field replaceable packaged refrigeration module to tubing formed in or on the chassis of the electronic system serves to create a cooling system wherein the temperature of the air surrounding the electronic system is lowered and the chassis of the electronic system itself becomes a refrigerator system for the electronic components therein.

FIELD OF THE INVENTION

[0001] The present invention relates to a refrigeration system forcooling electronic systems. More particularly, the invention relates toa method and apparatus for cooling electronic devices that includes afield and/or customer replaceable refrigeration module.

BACKGROUND OF THE INVENTION

[0002] Electronic components, such as microprocessors and other variousintegrated circuits, have advanced in at least two significant ways.First, feature sizes have moved into the sub-micron range therebyallowing larger numbers of transistors to be formed on a given surfacearea. This in turn has resulted in greater device and circuit density onthe individual chips. Second, in part due to the first advance discussedabove, microprocessors have increased dramatically in clock speed. Atpresent microprocessor speeds of 2.5 Gigahertz are coming to market andthe 3 and 4 Gigahertz range is rapidly being approached.

[0003] As a result of the advances in device density and microprocessorspeed discussed above, heat dissipation, which has always been a problemin the past, is rapidly becoming the limiting factor in microprocessorperformance. Consequently, heat dissipation and cooling is now theforemost concern and the major obstacle faced by designers of electronicsystems such as computers and servers.

[0004] As noted, heat dissipation has long been recognized as a seriousproblem limiting the performance of electronic components and systems.In the past, the solutions to the heat dissipation problem have beenmostly limited to air-based cooling systems such as fans, with only themost exotic military, scientific and custom electronic systems employingthe bulky and costly prior art liquid-based cooling solutions.

[0005] In the prior art, air-based cooling systems, such as fans andother forced air systems, have been the method of choice for severalreasons. First, the air-based cooling systems of the prior art weremodular and self-contained and were therefore field replaceable withminimal effort using standard tools. Second, air-based cooling systemswere compact and simple in both operation and installation, with minimalparts to fail or break and minimal added system complexity. Therefore,prior art air-based cooling systems were reliable.

[0006] In addition, and probably most importantly, in the prior art,air-based cooling systems could reasonably meet the cooling needs ofelectronic devices and systems so there was little motivation to move tothe more complex and potentially problematic liquid-based systems.However, as noted above, due to the advances in microprocessor speedsand device density, air-based cooling systems alone will most likely notbe a viable option for cooling electronic systems, such as computers andcomputer servers, that use the next generation of microprocessors.

[0007] As noted above, another possible prior art cooling system thatcould potentially provide the level of cooling required by electronicsystems using the next generation of microprocessors is liquid-basedcooling systems. Prior art liquid-based cooling systems typically used arefrigerant, such as R134A, that was circulated by a compressor. Inprior art liquid-based cooling systems the compressor was typically acrankshaft reciprocating compressor or a rotary compressor similar tothose used in home refrigerators.

[0008] As noted above, prior art liquid-based cooling systems have farmore potential cooling capability than air-based systems. However, inthe prior art liquid-based cooling systems, the crankshaft reciprocatingor rotary compressors were typically, by electronics industry standards,very large, on the order of tens of inches in diameter, very heavy, onthe order of pounds, and often required more power to operate than theentire electronic system they would be charged with cooling. Inaddition, the size and design of prior art liquid-based cooling systemsoften required that the major components of the prior art liquid-basedcooling system be centrally located, typically remote from theelectronic systems to be cooled. Consequently, unlike prior artair-based cooling systems, prior art liquid-based cooling systems werenot modular, were not self-contained, and often required specialexpertise and tools for maintenance and operation.

[0009] In addition, prior art liquid-based cooling systems employedcompressors that typically were highly orientation dependent, i.e., theycould not operate at angles of more than 30 or 40 degrees. Consequently,prior art liquid based cooling systems were particularly ill suited forthe electronics industry that stresses flexibility and often requiresorientation independent operation.

[0010] Given that, as discussed above, air-based cooling systems havereached their operational limits when it comes to cooling electronicsystems, such as computer servers, there is a growing realization thatsome other form of cooling system, such as liquid-based cooling systemswill need to be adopted by the electronics industry. However, asdiscussed above, prior art liquid-based cooling systems are far fromideal and, thus far, the industry has not adopted liquid-based coolingin any meaningful way because the problems associated with prior artliquid-based cooling systems are still thought to outweigh theadvantages these systems provide in terms of increased cooling capacity.

[0011] What is needed is a method and apparatus for cooling electronicsystems that has the cooling capacity and efficiency of a liquid-basedcooling system yet has the advantages of being modular, simple, andcompact like air-based cooling systems.

SUMMARY OF THE INVENTION

[0012] The present invention is directed to a cooling system forelectronic systems that includes a field and/or customer replaceablepackaged refrigeration module coupled to tubing formed within, oraround, the chassis of the electronic system, or subsystem, to becooled.

[0013] As noted above, according to the present invention, advances incompressor technology are incorporated in a field replaceable packagedrefrigeration module that is coupled to tubing formed in or on thechassis of the electronic system. According to the invention, the fieldreplaceable packaged refrigeration module is self-contained and isspecifically designed to have physical dimensions similar to those of astandard air-based cooling system, such as a fan or heat sink.

[0014] In one embodiment of the invention, the coupling of the fieldreplaceable packaged refrigeration module to tubing formed in or on thechassis of the electronic system serves to create a cooling systemwherein the temperature of the air surrounding the electronic system islowered, the entire system is bathed in cool air, and the chassis of theelectronic system itself becomes a refrigerator system for theelectronic components therein. In one embodiment of the invention, thefield replaceable packaged refrigeration module can be operatedintermittently, on an as needed basis, to minimize the power used by thesystem and to minimize the wear and tear of the moving parts. The netresult is the ability to manage the ambient temperature of the airwithin the electronic system chassis.

[0015] The cooling system of the invention is a modified liquid-basedcooling system and therefore provides the cooling capacity of a priorart liquid-based cooling systems. However, unlike prior art liquid-basedcooling systems, cooling system of the invention is modular and largelyself-contained. In addition, according to the invention, the fieldreplaceable packaged refrigeration module is field and/or customerreplaceable with minimal effort using standard tools.

[0016] According to the invention, each electronic system, such as acomputer server, includes its own the cooling system so that when theseelectronic systems are grouped into racks, each individual electronicsystem includes its own self-contained cooling system of the invention.Consequently, the failure of the cooling system for one electronicsystem does not affect the other systems in the rack and thoseunaffected systems can continue to operate while the faulty system isrepaired. This is in direct contrast to prior art liquid-based systemswherein multiple electronic systems such as computer servers, werecoupled to a single prior art cooling system so that if there was afailure anywhere in the cooling system, all the electronic systems wereaffected and had to be shut down.

[0017] In addition, unlike prior art liquid-based cooling systems, thecooling system of the invention is compact and simple in both operationand installation, with minimal parts to fail or break and minimal addedcomplexity. Therefore, unlike prior art liquid-based cooling systems,the cooling system of the invention is sturdy and reliable.

[0018] In addition, the field replaceable packaged refrigeration moduleportion of the present invention is specifically designed to beoperational in any orientation. Consequently, unlike prior artliquid-based cooling systems, the field replaceable packagedrefrigeration module portion of the present invention can be mounted,and operated, at any angle. This makes the cooling system of the presentinvention particularly well suited for use with electronic systems.

[0019] As discussed briefly above, and in more detail below, the coolingsystem of the present invention has the cooling capacity of aliquid-based cooling system and yet is modular, compact, simple indesign and simple to use, like an air-based cooling system.Consequently, the cooling system of the present invention can readilymeet the cooling needs of the next generation of electronic devices andsystems.

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The refrigeration system of the present invention will bedescribed in the following detailed description, with reference to theaccompanying drawings. In the drawings, the same reference numbers areused to denote similar components in the various embodiments.

[0021]FIG. 1 is a functional diagram of a field replaceable packagedrefrigeration module designed according to the principles of oneembodiment of the invention;

[0022]FIG. 2 is a longitudinal cross sectional view of an exemplarylinear compressor that may be used in the field replaceable packagedrefrigeration module depicted in FIG. 1 according to the principles ofone embodiment of the invention;

[0023]FIG. 3 is a cut-away perspective view a field replaceable packagedrefrigeration module positioned within an electronic device chassisaccording to the principles of one embodiment of the invention.

[0024]FIG. 4A shows an overhead view of one embodiment of a chassisdesigned according to the principles of the invention to include tubingformed into a tubing loop.

[0025]FIG. 4B shows a perspective view of one embodiment of a chassisdesigned according to the principles of the invention to include tubingformed into a tubing loop.

[0026]FIG. 4C shows one embodiment of a cooling system designedaccording to the principles of the invention including a chassis withtubing formed into a tubing loop that is coupled to field replaceablepackaged refrigeration module.

[0027]FIG. 5A shows a portion of a typical roll-bond evaporator wall.

[0028]FIG. 5B shows a perspective view of one embodiment of a chassisdesigned according to the principles of the invention to includeroll-bond evaporator walls.

[0029]FIG. 5C shows one embodiment of a cooling system designedaccording to the principles of the invention including a chassis withroll-bond evaporator walls coupled to a field replaceable packagedrefrigeration module.

[0030]FIG. 6 shows one embodiment of a cooling system designed accordingto the principles of the invention for use in a blade serverconfiguration.

DETAILED DESCRIPTION

[0031] According to the present invention, advances in compressortechnology (312 in FIG. 3) are incorporated in a field replaceablepackaged refrigeration module (300 in FIGS. 3, 4C and 5C) that iscoupled to tubing (401 in FIG. 4C and 551 in FIG. 5C) formed in, or on,the chassis (301 in FIG. 3, 400 in FIGS. 4A, 4B and 4C and 550 in FIGS.5B and 5C) of the electronic system to be cooled. According to theinvention, the field replaceable packaged refrigeration module isself-contained and is specifically designed to have physical dimensionssimilar to those of a standard air-based cooling system, such as a fanor heat sink.

[0032] In one embodiment of the invention, the coupling of the fieldreplaceable packaged refrigeration module to tubing formed in, or on,the chassis of the electronic system serves to create a cooling systemwherein the temperature of the air surrounding the electronic system islowered, the entire system is bathed in cool air, and the chassis of theelectronic system itself becomes a refrigerator system for theelectronic components therein.

[0033]FIG. 1 is a functional diagram of a field replaceable packagedrefrigeration module 10 designed according to one embodiment of theinvention. Referring to FIG. 1, field replaceable packaged refrigerationmodule 10 includes a compressor 12, a condenser 14, an optional receiver16, an expansion device 18 and an evaporator 20, all of which areconnected together in refrigeration loop 22 through which a workingfluid, such as water or ethanol, is circulated. As explained in moredetail below, according to one embodiment of the invention, evaporator20 is constructed either as tubing formed within the chassis of anelectronic system to be cooled or as roll-bond walls of the chassis ofan electronic system to be cooled.

[0034] As is well understood by those of ordinary skill in the art,compressor 12 compresses the refrigerant (not shown) into ahigh-pressure, high temperature liquid that is then conveyed tocondenser 14. At condenser 14, the refrigerant is allowed to cool beforebeing conveyed to receiver 16. From receiver 16, the refrigerant passesthrough expansion device 18, which may be, for example, a capillarytube, and into evaporator 20. The liquid refrigerant evaporates inevaporator 20 and in the process absorbs heat to produce the desiredcooling effect. From evaporator 20 the refrigerant is drawn back intocompressor 12 to begin another cycle through refrigeration loop 22.

[0035] In accordance with the present invention, compressor 12 is one ofseveral new generation compressors that are relatively small, on theorder of 2.0 inches in diameter and 3 to 4 inches long. In oneembodiment of the invention, compressor 12 is less than 1.7 inches indiameter and less than 4 inches long. One example of this new generationof compressors is the relatively new linear compressor now being used inthe more standard refrigeration, i.e., non-electronics, industry. In oneembodiment of the invention, compressor 12 is a linear compressor whoseoperation is controlled by drive circuit 26.

[0036] As discussed in more detail with respect to FIG. 2, a linearcompressor is a positive displacement compressor having one or more freefloating pistons that are driven directly by a linear motor. Thus, alinear compressor differs from a conventional reciprocating and rotarycompressor where the pistons are driven through a crankshaft linkage, orby a rotary motor through a mechanical linkage, respectively. Since thecapacity of any compressor is directly related to the size anddisplacement of the pistons, a linear compressor can typically be madesmaller than a crankshaft reciprocating or rotary compressor but canmaintain the same capacity since the displacement of the pistons is notdependent on the size of a mechanical linkage. In addition, since alinear compressor usually comprises fewer moving parts than a crankshaftreciprocating or rotary compressor, the linear compressor is typicallyquieter than a crankshaft reciprocating or rotary compressor.Furthermore, since the pistons of a double-piston linear compressor movein opposition to one another, the reaction forces of the pistons willcancel each other out and the vibrations that are commonly experiencedwith crankshaft reciprocating or rotary compressors will consequently besuppressed. Consequently, linear compressors offer many advantages overa crankshaft reciprocating compressor or a rotary compressor forapplication as compressor 12 in field replaceable packaged refrigerationmodule 10.

[0037] The linear compressors suitable for use as compressor 12 in fieldreplaceable packaged refrigeration module 10 can be any of a variety ofsingle, double or multiple-piston linear compressors that are known inthe art. For example, in one embodiment of the invention, linearcompressor 12 is a single-piston linear compressor of the type disclosedin U.S. Pat. No. 5,993,178, which is hereby incorporated herein byreference, or a double-piston linear compressor of the type disclosed inU.S. Pat. No. 6,089,836 or U.S. Pat. No. 6,398,52, all of which arehereby incorporated herein by reference.

[0038] Referring to FIG. 2, an exemplary linear compressor 120, suitablefor use as compressor 12 in FIG. 1, comprises a housing 28, first andsecond cylinders 30, 32 which are connected to, or formed integrallywith, housing 28, and first and second pistons 34, 36 which are slidablyreceived within first and second cylinders 30, 32, respectively. Theends of housing 28 are, in one embodiment, hermetically sealed, such asby end plates 38. In addition, each cylinder 30, 32 has an axialcenterline CL that is, in one embodiment, coaxial with that of the othercylinder. Furthermore, housing 28 is, in one embodiment, constructed ofa magnetically permeable material, such as stainless steel, and pistons34, 36 are optimally constructed of a magnetically indifferent material,such as plastic or ceramic.

[0039] In the embodiment of exemplary linear compressor 120 shown inFIG. 2, each piston 34, 36 is driven within its respective cylinder 30,32 by linear motor 40. Each motor 40 includes a ring-shaped permanentmagnet 42 and an associated electrical coil 44. In the embodiment of anexemplary linear compressor 120 shown in FIG. 2, magnet 42 is mountedwithin housing 28 and coil 44 is wound upon a portion of piston 34, 36.In one embodiment, magnet 42 is radially charged, and each motor 40includes a cylindrical core 46 mounted within housing 28 adjacent magnet42 to direct the flux lines (not shown) from magnet 42 across coil 44.In one embodiment, coil 44 is energized by an AC current, from drivecircuit 26 (FIG. 1), over a corresponding lead wire (not shown). In oneembodiment of the invention, drive circuit 26 is programmed such that,when the AC current is applied to coils 44 (FIG. 2), pistons 34, 36 willreciprocate toward and away from each other along the axial centerlineCL of cylinders 30, 32. In another embodiment, DC current is applied. Inone embodiment, spring 48, or similar means, may be connected betweeneach piston 34, 36 and adjacent end plate 38 to aid in matching thenatural frequency of piston 34, 36 to the frequency of the current fromdrive circuit 26 (FIG. 1).

[0040] The embodiment of an exemplary linear compressor 120 shown inFIG. 2 also includes a compression chamber 50 located within cylinders30, 32, between pistons 34, 36. During the expansion portion of eachoperating cycle of linear compressor 120, motors 40 will move pistons34, 36 away from each other. This will cause the then gaseousrefrigerant within evaporator 20 (FIG. 1) to be drawn into compressionchamber 50 (FIG. 2), through an inlet port 52 in housing 28. During thesuccessive compression portion of the operating cycle of exemplarylinear compressor 120, motors 40 will move pistons 34, 36 toward eachother. Pistons 34, 36 will consequently compress the then gaseousrefrigerant within compression chamber 50 into a liquid and eject itinto condenser 14 (FIG. 1), through an outlet port 54 (FIG. 2) inhousing 28. In one embodiment, suitable check valves 56, 58 are providedin inlet and outlet ports 52, 54, respectively, to control the flow ofrefrigerant through inlet and outlet ports 52, 54 during the expansionand compression portions of each operating cycle.

[0041] While a specific embodiment of a field replaceable packagedrefrigeration module 10 is discussed above that includes exemplarylinear compressor 120, those of skill in the art will recognize that thechoice of a linear compressor, or any particular compressor, for use ascompressor 12 in the discussion above was made for illustrationsimplicity and to avoid detracting from the invention by describingmultiple specific embodiments at one time. In other embodiments of theinvention appropriately sized rotary compressor, or other type ofcompressor, can be used as compressor 12. For instance, in variousembodiments of the invention, compressor 12 can be: a reciprocatingcompressor; a Swash-plate compressor; a rolling piston compressor; ascroll compressor; a rotary vane compressor; a screw compressor; anaerodynamic-turbo compressor; an aerodynamic-axial compressor; or anyother reciprocating, volumetric or aerodynamic compressor known in theart, or developed after this application is filed. Consequently, thepresent invention should not be read as being limited the particularembodiments discussed above using linear, or any specific, compressortypes.

[0042] Consequently, the present invention should not be read as beinglimited the particular embodiments discussed above using linear, or anyspecific, compressor types.

[0043] According to the principles of the invention, field replaceablepackaged refrigeration module 10 is mounted in the chassis of anelectronic system for use in cooling the electronic system. For example,it is often the case that many computer servers are housed within anenclosure/cabinet or “rack unit”. According to the invention, eachcomputer server would include it own cooling system and fieldreplaceable packaged refrigeration module 10.

[0044] In accordance with one industry standard, each rack unit has aheight of only 1.75 inches. This fact makes use of prior artliquid-based cooling systems extremely difficult, if not impossible, andmakes the extensive, and potentially disastrous, plumbing, discussedabove, a system requirement. In contrast, a single, or even multiple,field replaceable packaged refrigeration modules 10, designed accordingto the principles of the invention, can be positioned within the housingof the server, and/or on the rack units, to directly cool the airsurrounding the integrated circuits that are located within or on therack units.

[0045]FIG. 3 is a cut-away view a field replaceable packagedrefrigeration module 300 positioned within an electronic device chassis301. As discussed above, in accordance with one embodiment of theinvention, field replaceable packaged refrigeration module 300 is sizedsuch that, when positioned as shown in FIG. 3, field replaceablepackaged refrigeration module 300 will fit within a rack unit of aconventional computer server or a telecommunications rack.

[0046] In one embodiment of the invention, field replaceable packagedrefrigeration module 300 has a length 303 (FIG. 3) of approximately sixinches, a width 307 of approximately four inches, and a height 305 ofapproximately one and three-quarter inches. In another embodiment of theinvention, field replaceable packaged refrigeration module 300 has alength 303 of approximately five inches, a width 307 of approximatelyfour inches, and a height 305 of approximately one and three-quarterinches. Of course, those of skill in the art will recognize that length303, width 307 and height 305 of field replaceable packagedrefrigeration module 300 can be varied to meet the needs of specificapplications.

[0047] As shown in FIG. 3, in one embodiment of the invention, fieldreplaceable packaged refrigeration module 300 includes a housing 366which has generally open front and back sides 368, 370, a conventionalair-cooled condenser 314, which is mounted within housing 366 betweenopen front and back sides 368, 370, and a compressor 312 which isconnected to housing 366. As discussed above, in one embodiment of theinvention, compressor 312 is a linear compressor driven by a drivecircuit (not shown) in a manner similar to that discussed above. Asdiscussed in more detail below, in another embodiment of the invention,field replaceable packaged refrigeration module 300 is coupled to tubingformed on (FIG. 4C) or in (FIG. 5C) electronic device chassis 301.

[0048] In one embodiment of the invention, condenser 314 is cooled by aflow of air from a system fan (not shown) that is mounted in chassis301. In addition, in one embodiment of the invention, field replaceablepackaged refrigeration module 300 is connected to chassis 301 with anumber of standoffs 374 and screws 376.

[0049] As noted above, according to the present invention, fieldreplaceable packaged refrigeration module 300 is coupled to tubingformed in, or on, chassis 301 of the electronic system. The coupling offield replaceable packaged refrigeration module 300 to tubing formed in,or on, chassis 301 of the electronic system serves to create a coolingsystem wherein the evaporator of the cooling system is the tubing loopformed in or on chassis 301 and temperature of the air surrounding theelectronic system is lowered, the entire system is bathed in cool air,and chassis 301 of the electronic system itself becomes a refrigeratorsystem for the electronic components therein.

[0050]FIG. 4A shows an overhead view of one embodiment of a chassis 400designed according to the invention to include tubing 401 formed intotubing loop 403. According to the invention, tubing loop 403 acts as theevaporator for the cooling system of the invention. FIG. 4B shows aperspective view of chassis 400 and tubing 401 formed into tubing loop403. According to the invention, tubing 401 making up tubing loop 403can be any one of a variety of materials such as various metals and/orsynthetic and natural materials known in the art. In this embodiment ofthe invention, tubing 401 is attached to chassis 400 using any suitablemethod such as glues, solder, mechanical attachment means, or evenintegral formation.

[0051] Those of skill in the art will further recognize that the amountof tubing 401, and the positioning of tubing 401, can be varied to meetthe cooling needs of the particular electronic system being cooling. Forinstance, tubing 401 can be switched back and forth to form coils ormultiple tub lengths can be run parallel to each other to increasetubing 401 surface area and increase the cooling capacity of tubing loop403.

[0052]FIG. 4C shows cooling system 450 of the invention includingchassis 400 with tubing 401 formed into tubing loop 403 that is coupledto field replaceable packaged refrigeration module 300 by connectiontube 451. Also shown in FIG. 4C are condenser 314 and compressor 312(discussed in more detail above with respect to FIG. 3) and tubing 453of field replaceable packaged refrigeration module 300.

[0053] During the normal operation of cooling system 450 of theinvention, relatively high-pressure liquid refrigerant from compressor312 is conveyed through tubing 453 to condenser 314. In one embodimentof the invention, the high-pressure liquid refrigerant is cooled incondenser 314 by the flow of air from a system fan (not shown). Therefrigerant is then conveyed through connection tube 451 to tubing loop403 that acts as an evaporator. The refrigerant evaporates in tubingloop 403 and in the process absorbs heat and cools the air withinchassis 400. The now gaseous refrigerant is then drawn back intocompressor 312 through conduit 480. This cycle is then repeated asrequired to produce a desired cooling effect for the electronic system(not shown) housed in chassis 400. Consequently, using the method andapparatus of the invention, the temperature of the air surrounding theelectronic system (not shown) housed in chassis 400 is lowered, theentire system is bathed in cool air, and chassis 400 becomes arefrigerator system for the electronic components therein (not shown).

[0054] In another embodiment of the invention, the walls of theelectronic system chassis itself are formed as roll-bond evaporators.Roll-bond evaporator walls are typically formed by pressing two or moresheets of wall material, typically metal, such that within the wallthere exists two areas or compartments, typically one for holding arefrigerant and one with no refrigerant.

[0055]FIG. 5A shows a portion of a typical roll-bond evaporator wall500. Portion of roll-bond evaporator wall 500 includes: first outer wallsurface 501, that would typically be exposed to the air outside thechassis; second outer wall surface 503, that would typically be exposedto the air inside the chassis; first inner wall 505; and second innerwall 507. First inner wall 505 and second inner wall 507 define area 509that is physically isolated from area 511 by first inner wall 505 andsecond inner wall 507. In a typical roll-bond evaporator wall, area 509would contain refrigerant (not shown) and area 511 would not.

[0056]FIG. 5B shows a perspective cut-away view of one embodiment of achassis 550 designed according to the principles of the invention toinclude roll-bond evaporator walls 551 formed into an evaporator loop553.

[0057]FIG. 5C shows one embodiment of a cooling system 580 designedaccording to the principles of the invention including chassis 550 withroll-bonded evaporator walls 551 coupled to field replaceable packagedrefrigeration module 300 by connection tube 555 and connection port 557.Also shown in FIG. 5C are condenser 314 and compressor 312 (discussed inmore detail above with respect to FIG. 3) and tubing 559 of fieldreplaceable packaged refrigeration module 300.

[0058] During the normal operation of cooling system 580 of theinvention, relatively high-pressure liquid refrigerant from compressor312 is conveyed through tubing 559 to condenser 314. In one embodimentof the invention, the high-pressure liquid refrigerant is cooled incondenser 314 by the flow of air from a system fan (not shown). Therefrigerant is then conveyed through a connection tube 555 to roll-bondevaporator wall 551 and evaporator loop 553 that acts as an evaporator.The refrigerant evaporates in evaporator loop 553 and in the processabsorbs heat and cools the air within chassis 550. The now gaseousrefrigerant is then drawn back into compressor 312 through conduit 561.This cycle is then repeated as required to produce a desired coolingeffect for the electronic system (not shown) housed in chassis 550.Consequently, using the method and apparatus of the invention, thetemperature of the air surrounding the electronic system (not shown)housed in chassis 550 is lowered, the entire system is bathed in coolair, and chassis 550 becomes a refrigerator system for the electroniccomponents therein (not shown).

[0059] The cooling system of the invention can also be used in bladeserver applications to cool either individual blade servers or groups ofblade servers. FIG. 6 shows one embodiment of a blade-cooling system 601designed according to the principles of the present invention for use ina blade server frame 603 to cool a blade server 605. As shown in FIG. 6,blade-cooling system 601 includes: condenser 614; compressor 612;evaporator 607; fan 609; and connecting tubes 651, 653 and 655. As withthe embodiments of the invention discussed above, in one embodiment ofblade-cooling system 601, compressor 612 is a linear compressor drivenby a drive circuit (not shown) in a manner similar to that discussedabove.

[0060] According to the invention, blade-cooling system 601 isself-contained within a blade-cooling system housing 611, also calledchassis 611. In one embodiment of the invention chassis 611 hasdimensions approximately identical to those of a blade server 605 sothat blade-cooling system 601 fits into a blade server station, such asblade server stations 613 and 615 in FIG. 6, within blade server frame603. In this way, individual blade-cooling cooling system s 601 can beplaced directly next to the blade server 605 they are intended to cooland the blade-cooling systems 601 can be readily replaced in the fieldon a “plug and play” basis.

[0061] During the normal operation of blade-cooling system 601 of theinvention, relatively high-pressure liquid refrigerant from compressor612 is conveyed through tubing 653 to condenser 614. In one embodimentof the invention, the high-pressure liquid refrigerant is cooled incondenser 614 by the flow of air from fan 609. The refrigerant is thenconveyed through connection tube 655 to evaporator 607. Evaporator 607is then placed in thermal contact with blade server 605 within bladeserver frame 603. The refrigerant evaporates in evaporator 607, and inthe process absorbs heat and cools blade server 605 and/or the airsurrounding blade server 605. The now gaseous refrigerant is then drawnback into compressor 612 through tubing 651. This cycle is then repeatedas required to produce a desired cooling effect for blade server 605housed in blade server frame 603.

[0062] As shown above, according to the present invention, advances incompressor technology are incorporated in a field replaceable packagedrefrigeration module that is coupled to tubing formed in, or on, thechassis of the electronic system to be cooled. According to theinvention, the field replaceable packaged refrigeration module isself-contained and is specifically designed to have physical dimensionssimilar to those of a standard air-based cooling system, such as a fanor heat sink.

[0063] In one embodiment of the invention, the coupling of the fieldreplaceable packaged refrigeration module to tubing formed in, or on,the chassis of the electronic system serves to create a cooling systemwherein the temperature of the air surrounding the electronic system islowered, the entire system is bathed in cool air, and the chassis of theelectronic system itself becomes a refrigerator system for theelectronic components therein. In one embodiment of the invention, thefield replaceable packaged refrigeration module can be operatedintermittently, on an as needed basis, to minimize the power used by thesystem and to minimize the wear and tear of the moving parts. The netresult is the ability to manage the ambient temperature of the airwithin the electronic system.

[0064] The cooling system of the invention is a modified liquid-basedcooling system and therefore provides the cooling capacity of a priorart liquid-based cooling systems. However, unlike prior art liquid-basedcooling systems, cooling system of the invention is modular and largelyself-contained. In addition, according to the invention the fieldreplaceable packaged refrigeration module is field and/or customerreplaceable with minimal effort using standard tools.

[0065] According to the invention, each electronic system, such as acomputer server, includes its own the cooling system of the invention sothat when these electronic systems are grouped into racks, eachindividual electronic system includes its own self-contained coolingsystem. Consequently, the failure of the cooling system for oneelectronic system does not affect the other systems in the rack andthose unaffected systems can continue to operate while the faulty systemis repaired. This is in direct contrast to prior art liquid-basedsystems wherein multiple electronic systems such as computer servers,were coupled to a single prior art cooling system so that if there was afailure anywhere in the cooling system, all the electronic systems wereaffected and had to be shut down.

[0066] In addition, unlike prior art liquid-based cooling systems, thecooling system of the invention is compact and simple in both operationand installation, with minimal parts to fail or break and minimal addedcomplexity. Therefore, unlike prior art liquid-based cooling systems,the cooling system of the invention is sturdy and reliable.

[0067] In addition, the field replaceable packaged refrigeration moduleportion of the present invention is specifically designed to beoperational in any orientation. Consequently, unlike prior artliquid-based cooling systems, the field replaceable packagedrefrigeration module portion of the present invention can be mounted,and operated, at any angle. This makes the cooling system of the presentinvention particularly well suited for use with electronic systems.

[0068] As discussed above, the cooling system of the present inventionhas the cooling capacity of a liquid-based cooling system and yet ismodular, compact, simple in design and simple to use, like an air-basedcooling system. Consequently, the cooling system of the presentinvention can readily meet the cooling needs of the next generation ofelectronic devices and systems.

[0069] It should be recognized that, while the present invention hasbeen described in relation to the specific embodiments thereof discussedabove, those skilled in the art might develop a wide variation ofstructural and operational details without departing from the principlesof the invention.

[0070] As one example, the choice of a linear compressor, or anyparticular linear compressor, for use as compressor 312 in thediscussion above was made for illustration simplicity and to avoiddetracting from the invention by describing multiple specificembodiments at one time. In other embodiments of the invention,appropriately sized rotary compressors, or other compressors, can beused as compressor 312. For instance, in various embodiments of theinvention, compressor 312 can be: a reciprocating compressor; aswash-plate compressor; a rolling piston compressor; a scrollcompressor; a rotary vane compressor; a screw compressor; anaerodynamic-turbo compressor; an aerodynamic-axial compressor; or anyother reciprocating, volumetric or aerodynamic compressor known in theart, or developed after this application is filed. Consequently, thepresent invention should not be read as being limited the particularembodiments discussed above using linear, or any specific, compressortypes.

[0071] As another example, specific dimensions were discussed above asexamples of possible values for the length, width and height 305 offield replaceable packaged refrigeration module 300. Those of skill inthe art will recognize that length 303, width 307 and height 305 offield replaceable packaged refrigeration module 300 can be varied forspecific applications and that the present invention should not be readas being limited the particular embodiments discussed above with theparticular dimensions discussed by way of illustration.

What is claimed is:
 1. A cooling system for an electronic device comprising: an electronic device chassis, said electronic device chassis comprising tubing formed into a tubing loop within said electronic device chassis; a packaged refrigeration module, said packaged refrigeration module comprising: a packaged refrigeration module housing; refrigerant; a compressor; a condenser; and an expansion device; wherein, said compressor, said condenser, and said expansion device of said packaged refrigeration module and said tubing loop of said electronic device chassis are coupled together in a refrigeration loop within said electronic device chassis.
 2. The cooling system for an electronic device of claim 1; wherein, said packaged refrigeration module has a width of approximately 4 inches, a length of approximately 5 inches and a height of approximately 1.75 inches.
 3. The cooling system for an electronic device of claim 1; wherein, said compressor is a single piston linear compressor.
 4. The cooling system for an electronic device of claim 1; wherein, said compressor is a dual-piston linear compressor.
 5. The cooling system for an electronic device of claim 1; wherein, said compressor is a multi-piston linear compressor.
 6. The cooling system for an electronic device of claim 1; wherein, said compressor is a rotary compressor.
 7. The cooling system for an electronic device of claim 1; wherein, said compressor is a reciprocating compressor.
 8. The cooling system for an electronic device of claim 1; wherein, said compressor is a rolling piston compressor.
 9. The cooling system for an electronic device of claim 1; wherein, said compressor is a rotary vane compressor.
 10. The cooling system for an electronic device of claim 1; wherein, said compressor is a screw compressor.
 11. The cooling system for an electronic device of claim 1; wherein, said compressor is a swash-plate compressor.
 12. The cooling system for an electronic device of claim 1; wherein, said compressor is a scroll compressor.
 13. A cooling system for an electronic device comprising: an electronic device chassis, said electronic device chassis comprising at least one roll-bond evaporator panel forming at least a portion of said electronic device chassis; a packaged refrigeration module, said packaged refrigeration module comprising: a packaged refrigeration module housing; refrigerant; a compressor; a condenser; and an expansion device; wherein, said compressor, said condenser, and said expansion device of said packaged refrigeration module and said at least one roll-bond evaporator panel forming at least a portion of said electronic device chassis are coupled together in a refrigeration loop within said electronic device chassis.
 14. The cooling system for an electronic device of claim 13; wherein, said packaged refrigeration module has a width of approximately 4 inches, a length of approximately 5 inches and a height of approximately 1.75 inches.
 15. The cooling system for an electronic device of claim 13; wherein, said compressor is a single piston linear compressor.
 16. The cooling system for an electronic device of claim 13; wherein, said compressor is a dual-piston linear compressor.
 17. The cooling system for an electronic device of claim 13; wherein, said compressor is a multi-piston linear compressor.
 18. The cooling system for an electronic device of claim 13; wherein, said compressor is a rotary compressor.
 19. The cooling system for an electronic device of claim 13; wherein, said compressor is a reciprocating compressor.
 20. The cooling system for an electronic device of claim 13; wherein, said compressor is a rolling piston compressor.
 21. The cooling system for an electronic device of claim 13; wherein, said compressor is a rotary vane compressor.
 22. The cooling system for an electronic device of claim 13; wherein, said compressor is a screw compressor.
 23. The cooling system for an electronic device of claim 13; wherein, said compressor is a swash-plate compressor.
 24. The cooling system for an electronic device of claim 13; wherein, said compressor is a scroll compressor.
 25. A blade-cooling system, said blade-cooling system comprising: a blade-cooling system housing; refrigerant; a compressor; a condenser; an expansion device; and an evaporator; wherein, said compressor, said condenser, and said expansion device and said evaporator of said blade-cooling system are coupled together in a refrigeration loop within said blade-cooling system housing; further wherein; said blade-cooling system housing is sized such that said blade-cooling system fits within a blade server station in a blade server frame.
 26. The blade-cooling system of claim 25; wherein, said blade-cooling system housing has a width of less than three inches, a length of less than approximately six inches and a height of less than six inches.
 27. The blade-cooling system of claim 25; wherein, said compressor is a single piston linear compressor.
 28. The blade cooling of claim 25; wherein, said compressor is a dual-piston linear compressor.
 29. The blade cooling of claim 25; wherein, said compressor is a multi-piston linear compressor.
 30. The blade cooling of claim 25; wherein, said compressor is a rotary compressor.
 31. The blade-cooling system of claim 25; wherein, said compressor is a reciprocating compressor.
 32. The blade cooling of claim 25; wherein, said compressor is a rolling piston compressor.
 33. The blade cooling of claim 25; wherein, said compressor is a rotary vane compressor.
 34. The blade-cooling system of claim 25; wherein, said compressor is a screw compressor.
 35. The blade-cooling system of claim 25; wherein, said compressor is a swash-plate compressor.
 36. The blade-cooling system of claim 25; wherein, said compressor is a scroll compressor. 